FMEA失效模式和效果培訓教材

本資料來源FailureModeandEffectAnalysis(FMEA)

失效模式和效果分析LearningObjectives

學習目的GiveageneralintroductiontoFMEAprinciples.

介紹FMEA的基本原理.

Provideastep-by-stepguidanceinperformingFMEA

為實施FMEA提供指導.TheobjectiveofthisChapteristo本章節(jié)的目的是FMEADefinitionofFMEA

FMEA定義(I)FMEA:FailureModeandEffectsAnalysisFMEA：失效模式和效果分析Aprocedureinwhicheachpotentialfailuremodeineverysub-itemofanitemisanalyzedtodetermineitseffectonothersub-itemsandontherequiredfunctionoftheitem.FMEA是一個過程，在這個過程中對每個分項目的潛在失效模式進行分析，確定失效模式對于其他分項目和主項目的功能的影響Takenfrom“TheCertifiedQualityEngineerHandbook”ASQDefinitionofFMEA

FMEA定義(II)FMEA:FailureModeandEffectsAnalysisFMEA：失效模式和效果分析FMEAisastructuredanalysistoanticipatethe

potentialfailuresofadesignorprocessbeforetheyoccur.Allaspectsofeachpotentialfailurearestudiedtoidentifythemosteffectivepreventiveactions.FMEA是結構化的分析方法。用它在設計或過程的失效模式發(fā)生之前就預見潛在的失效.然后全面分析失效的各方面并識別最有效的預防措施.AnotherDefinitionForFMEA(III)FMEAisasystematicapproachusedtoexamine

potentialfailuresandpreventtheiroccurrence.Itenhancesanengineer’sabilitytopredictproblemsandprovidesasystemofranking,or

prioritization,sothe

mostlikelyfailuremodescanbeaddressedFMEA

是用來調查潛在失效及預防其再發(fā)生的系統(tǒng)化方法。這方法可以幫助提高工程師預知問題的能力，提供一套依風險大小順序排列失效的系統(tǒng)，以讓我們能針對最可能的失效模式先采取對策DefinitionofFMEA

FMEA定義Identifyandevaluate

thepotentialfailuremodes

ofaproduct/processandtheeffectsofthatfailure

識別和評估一個產品或過程的潛在失效模式及其影響；2.Listdowntheactionswhichcouldeliminateorreducethechanceofthepotentialfailureoccurring

確定能排除或減少潛在失效發(fā)生的機率的措施；3.

Documentalltheelementsforreviewandaction

文件化整個過程。AnFMEAcanbedescribedasasystematicgroupofactivitiesintendedto:FMEA是一系列系統(tǒng)化的活動，其目的是

：PropertiesofFMEA

FMEA的特點FMEAbeginswithadefinitionofallthe

functionsaprocessissupposedtoperform.FMEA開始于一個過程所有功能的定義ManufacturingEngineer制造工程師SupplierQuality供應商質量DesignEngineer設計工程師ProgramManagement程序管理Production產品ReliabilityEngineer可靠性工程師Teamwork團隊力量

FMEAmustbeperformedbyateaminordertoensureitseffectivenessFMEA須由小組進行,以確保其有效PropertiesofFMEA

FMEA的特點ThePurposeofFMEA

FMEA的目的Toidentifypotentialfailuremodesandratetheseverityoftheireffects識別潛在失效模式并評估他們影響的嚴重性Toidentifycriticalcharacteristicsandsignificantcharacteristics識別關鍵特性和重要特性Torankpotentialdesignandprocessdeficiencies評估潛潛在的的設計計和工工序不不足Reducetheproductdevelopmentcycle-timeandhencecost減少產產品開開發(fā)時時間和和成本本Tofocusoneliminatingandpreventingproductandprocessproblems聚焦于于產品品和工工序問問題的的消除除，并并防止止問題題再次次發(fā)生生ThePurposeofFMEAFMEA的目的的Background背景Bylate80’’s,FMEAisusedbyautomotivemanufacturersandtheirsupplierstoreducetheliabilitycost.到80年代末末，汽汽車工工業(yè)和和他們們的供供貨商商也開開始實實施FMEA，藉此此減低低責任任成本本Developedinearly60’’sbyNASAto““fail-proof””Apollomissions.60年代初初，由由美國國太空空空署署在阿阿波羅羅任務務中發(fā)發(fā)展起起來的的。Adoptedinearly70’’sbyUSNavytodevelopMIL-STD-1629.70年代初初，被被美國國海軍軍采用用。TypesofFMEAFMEA的類型型Itiswidelyusedinbothmanufacturingandtransactionalareas在制造造和服服務流流程中中都可可以使使用SYSTEM系統(tǒng)FMEASystemFMEAisusedtoanalyzesystemsandsubsystemsintheearlyconceptualdesignstages.SFMEA是用來來在早早期構構思設設計階階段分分析系系統(tǒng)與與子系系統(tǒng)DESIGN設計FMEADesignFMEAisusedtoanalyzeproductsbeforetheyarereleasedtoproductionDFMEA是用來來在生生產發(fā)發(fā)布前前分析析產品品。PROCESS過程FMEAProcessFMEAisusedtoanalyzemanufacturing,assemblyandadministrativeprocessesPFMEA用來分分析制制造、、裝配配和管管理過過程WhenShouldWeImplementFMEA?應在什什么時時候實實施FMEA？WeShouldStartFMEA我們應應開始始FMEAASEARLYASPOSSIBLE越早越越好！！StartandEndprocess開始和結束束SYSTEM系統(tǒng)DESIGN設計PROCESS過程START開始Aftersystemfunctionsaredefined,beforespecifichardwareisselected當系統(tǒng)功能定義后，在特殊硬件選定前。Afterproductfunctionsanddesignconceptsaredefined

butbeforethedesigniscompleted當產品功能和設計概念定義后，在設計完成前Whenpreliminarydrawingsareavailablebutbefore

toolingdesigniscompleted當初始圖紙已應用，但在工裝設計完成前END結束Whentheprojectisturnedovertodesign當項目轉化成設計時Whenfinaldrawingsarereleased當最終圖紙發(fā)布前。Whentheproductreachesendoflifeorisremoved

fromproduction當該產品壽命終止或不再生產ProcessFMEAFormat過程FMEA格式PFMEA圖表產品：:FMEA編號：過程FMEA過程/操作；第頁頁共頁頁計劃編制參參考：:日期：編制：城市過程描述潛在失效模模式S潛在失效的起因O現(xiàn)行控制DRPN優(yōu)先措施責任人和完成日期采取的措施施措施結果潛在失效后后果功能SODRPN探測度頻度數(shù)嚴重度RPN=SxOxD糾正措施ProcessFailureMode過程失效模模式Itisthemannerinwhichtheprocesscouldfailtoperformitsintendedfunction.潛在失效模模式是過程程可能發(fā)生生的不滿足足其原有功功能的形式式Thefailuremodeofaparticularprocessstepcouldbeacausetoasubsequentsteporaneffectofthefailureinapreviousoperation.某一工序的的失效模式式可能是后后續(xù)操作（（下道工序序）的起因因，或前期期操作（前前道工序））相關的潛潛在失效的的后果。ProcessFailureMode過程失效模模式EffectforPreviousOperationistheCauseforNextOperation前工序的的的后果，是是后工序的的原因PREVIOUSOPERATION前道工序NEXTOPERATION下道工序EFFECT后果FAILUREMODE失效模式CAUSE原因PotentialCauses潛在原因ProcessFMEAconsidersprocessvariabilitydueto:5M+E過程FMEA考慮是由于于如下原因因造成的過過程變異性性:5M+EMACHINE機器ENVIRONMENT環(huán)境MEASUREMENT測量MAN人員METHOD方法MATERIAL物料CurrentControls現(xiàn)行控制CurrentProcessControlsaredescriptionsofthecontrolsthat現(xiàn)行控制是是對以下控控制的描述述eitherpreventtotheextentpossiblethefailuremodefromoccurring盡可能的防防止失效模模式的發(fā)生生ordetectthefailuremodeshoulditoccur或當失效模模式發(fā)生時時能夠查覺覺它Assessmentoftheabilitytodetectthefailurebeforemovetothenextprocessorshippedtothecustomer.在產品制移移交下道工工序前或交交付給客戶戶前，對查查覺失效能能力的評估估CurrentControls現(xiàn)行控制Capabilityofallcontrolsintheprocesstopreventescapes過程中預防防壞品流出出的所有控控制能力Testing檢測SPC統(tǒng)計過程控控制GaugeR&R量化重復性性和再現(xiàn)性性ProcessCapabilityStudy過程能力分分析SampleInspection抽樣檢驗ProcessAudit過程審核CurrentControls現(xiàn)行控制ScoringCategories評分類別Scoresareassignedtothefollowing3categories:對以下3類進行評分分：SEVERITY(S)嚴重度Theseriousnessofthepotentialfailuremodetothecustomer.Thecustomerincludeslocalsystem,nextlevelandenduser.Severityappliestotheeffectonly.潛在失效模式對客戶的嚴重度。這里所指的客戶包括系統(tǒng)，下個工序和最終用戶。嚴重度只適用于結果OCCURRENCE(O)發(fā)生頻率Howfrequentaspecificcausewilloccurandresultinaspecificfailuremode.Theoccurrencerankingnumberhasameaningratherthanavalue.造成某種失效模式的某個原因多長時間發(fā)生一次。發(fā)生頻率的重點并不在于它的得分，而是它的意義DETECTION(D)可探測度Probabilityofthecurrent/proposedcontrolmechanismtodetectandidentifythefailuremode是指當前或將要用來探測或鑒別失效模式的控制設備能多探測出失效模式的概率RiskPriorityNumber風險優(yōu)先指指數(shù)RPN=OxSxD/EWhere:其中O--Occurrencex發(fā)生頻率S--Severityx嚴重性D--Detection可探測性orE–Effectiveness有效性ShortcomingsofRPNRPN的缺點A845160B485160SAMERESULT!相同的結果果FailureMode失效模式S嚴重度O發(fā)生頻度D/E有效性RPN風險優(yōu)先指指數(shù)ActionPriority措施優(yōu)先級級別ABCDOver200100-19926-991-25PRIORITY優(yōu)先級別RPNRANGERPN范圍Thisisforreferenceonly僅供參考FMEABestAppliedFor

FMEA最適合應用用于什么？？Thereisachangefrompreviousversion同以前相比比有變化的的Processcontrolishighlyoperatordependent過程控制主主要依賴于于操作員Newtechnologyintroduced包含新技術術Haveahighdegreeofvariation變異較多的的Thereisachronicallyproblem長期存在問問題的FMEAisbestappliedforthefollowingdesignorprocesses...FMEA最適合應用用于以下設設計或過程程……HowIsFMEAAppliedinSixSigmaFMEA在6Sigma中的運用FMEAinputistheprocessflowchartFMEA的輸入是流程圖。Input輸入ProcessFlowchart流程圖Process過程FMEAOutput輸出HighPriorityFailureModes&CausesofFailure高優(yōu)先級失失效模式及及失效原因因FMEAisananalyticalprocess.FMEA是一個分析的過程。。FMEAoutputisprioritizedkeyprocessinputvariables.FMEA的輸出是一一個有優(yōu)先級級的失效模式和失失效原因。。FMEAExample-Step1FMEA例子-步驟11.Fillintheheaderinformation填寫標題信信息(1).Describetheprocess流程描述(2).NumbertheFMEA編號(3).IdentifytheBB/GB確定人選(4).Identifypagenumbers確定頁數(shù)(5).Listteammembers列出小組成成員(6).Nametheprepared填表人(7).EntertheFMEAdate輸入FMEA日期(8).Entertherevisiondate輸入改版日日期(1)(3)(5)(2)(4)(6)(7)(8)FMEAExample-Step2

FMEA例子-步驟22.Writedowntheprocesssteps.填寫流程程步驟AddallvalueaddedprocessstepsfromtheprocessmaptotheFMEAform.把所有增增值流程程步驟填填入FMEA表格Start開始End結束Step2AStep2BStep2CStep1ApplicationofWaxinsidedoorGood?Rework返工YesNoFMEAExample-Step3FMEA例子-步驟3Writedownthefunctionsforeachprocessstep對每個流流程步驟驟，列出出功能Functionsarestatementsofwhattheprocessstepshouldaccomplish.Itcanalsobespecificationsifpossible.功能可以以是規(guī)格格（如果果可行）），或者是流流程步驟驟所要完完成工作作的描述述FMEAExample-Step4FMEA例子-步驟44.1.Writedownthepotentialfailuremodeforeachfunction.對每個功功能，列列出潛在在失效模式FMEAKeyPointsAboutStep4.1步驟4.1中的FMEA的重點KeypointsaboutStep4.1:步驟4.1中的重點點:Failuremodesarestatementsofdeficiencyoffunctions.失效模式是對對功能的負面面描述Failuremodesarenotcauses.失效模式不是是原因.Donotdiscussthecauses.Leavethecausestostep4.4不要在此階段段討論原因，，在步驟4.4中才討論原因因4.1.Writedownthepotentialfailuremodeforeachfunction.對每個功能，，列出潛在失失效模式FMEAExample-Step4.2

FMEA例子-步驟4.24.2.Foreachfailuremode,listtheeffectoffailure對每個失效模模式，列出失效效的后果FMEAKeyPointsAboutStep4.2步驟4.2中FMEA的重點KeypointsaboutStep4.2:步驟4.2中的重點Listonly““worstcase”effectsoffailure.只列出最壞的的失效后果Describewhatactuallyhappenswhenthefailuremodeoccurs,ratherthanusinggeneralstatementlike“PartFailed”or“RejectedbyCustomer””抓住失效模式式發(fā)生時實際際的情形，避避免概括性描描述，如“部部件不合格””或“客戶投投訴”。Themorespecificisthedescriptioninthiscolumn,theeasierwillbethelatersteps(estimatingseverity&listingcauses).通過本節(jié)的具具體描述，使使后面的步驟驟（估計嚴重重性和找出原原因）變的容容易。4.2.Foreachfailuremode,listtheeffectoffailure對每個失效模模式，列出失效效的后果FMEA-Step4.3步驟4.34.3.Writedowntheseverityforeacheffectoffailure對每個失效的的后果，評估嚴重重性FMEA-Step4.3:AIAG*SeverityGuidelines

FMEA-Step4.3:AIAG*嚴重性指南Note:AIAGistheAutomotiveIndustryActionGroup,whichcurrentlycompilestheFMEAstandardsfortheNorthAmericanAutoIndustry.備注：AIAG是汽車工業(yè)行行動集團縮寫寫，為目前美美國汽車工業(yè)業(yè)FMEA編寫者FMEAKeyPointsAboutStep4.3步驟4.3FMEA的重點4.3.Writedowntheseverityforeacheffectoffailure對每個失效后后果評估其嚴重性KeypointsaboutStep4.3:步驟4.3的重點：Someusersadopta1to5system.有些用戶采用用1-5分的系統(tǒng)Whateverguidelinesareused…無論使用那種種指南……KeepacopywithyourFMEA.保存FMEA的附件Alwaysmakethehighestnumbermostsevere,thelowestleastsevere.始終讓最高嚴嚴重性為最高高分，最低嚴嚴重性為最最低分FMEAExample-Step4.4

FMEA例子-步驟4.44.4.Writedownthecausesforeachfailuremode對每個失效模模式，列出原原因FMEAKeyPointsAboutStep4.4對每個失效模模式，列出原原因KeypointsaboutStep4.4:步驟4.4的重點UseCauseandEffectDiagramstodoathoroughinvestigationofcausesfortoughfailuremodes.對主要失效模模式用因果圖圖作一次徹底底的原因分析析Sometimeshypothesistestingcanbeusefulindemonstratingwhetheracauseisstrong.有時假設檢驗驗能有助于證證明一個原因因是否強弱4.4.Writedownthecausesforeachfailuremode.對每個失效模模式，列出原原因Verifytheimportanceofcausestoreducethelistofcauses.通過驗證列出出原因的重要要性，防止有有太多的原因因Ifthecausesarealreadyknowntoeveryone,youmaynotcometotherealrootcause.如果你列出那那些是大家都都知道的原因因，你可能仍仍未找到根本本原因FMEAExample-Step4.5

FMEA例子-步驟4.54.5Assessthelikelihoodofoccurrence.評估發(fā)生頻率率FMEAExample-Step4.5:AIAG*OccurrenceGuidelinesAIAG發(fā)生頻率指南南Note:AIAGistheAutomotiveIndustryActionGroup,whichcurrentlycompilestheFMEAstandardsfortheNorthAmericanAutoIndustry.備注：AIAG是汽車工業(yè)行行動集團的縮縮寫，目前北北美汽車工業(yè)業(yè)FMEA標準編寫者FMEAKeyPointsAboutStep4.5步驟4.5FMEA的重點KeypointsaboutStep4.5:步驟4.5的重點Someusersadopta1to5system.有些用戶采用用1-5分的系統(tǒng)Whateverguidelinesareused…無論使用那種種指南……KeepacopywithyourFMEA.保存FMEA的附件Alwaysmakethehighestnumbermostfrequent,thelowestleastfrequent.始終讓最頻繁繁者為最高分分，最不頻繁繁者為最低分分4.5Assessthelikelihoodofoccurrenceforeachcauseoffailure.對每個失效原原因評估發(fā)生生頻率FMEAExample-Step4.6

FMEA例子-步驟4.64.6.Writedownlistthecurrentprocesscontrolsforeachcauseoffailure.對每個失敗的的原因，列出現(xiàn)有有流程的控制FMEAKeyPointsAboutStep4.6步驟4.6FMEA的重點KeypointsaboutStep4.6:步驟4.6的重點Writedowntheactualcontrols,notthe““Wannabe”controls.確保列出實際際控制方法,不要列“最理理想”的控制制Bebrutallyhonest,ifthereisnocontrol,justsayit.要坦白誠實，，如果沒有控控制要說出來來Normally,thereisnocontrolforthecauseofthefailuremode;butthereisacontroltodetectthefailuremodeitself.一般情況是，，對失效模式式的原因沒有有控制，但對對探測失效模模式本身有控控制4.6.Writedownthecurrentprocesscontrolsforeachcauseoffailure.對每個失敗的的原因，列出現(xiàn)有有過程的控制ProcessControlExample過程控制案例例Inaninjectionmoldingprocess,injectionpressureofover8000pieze(kilo-pascals)leadstoasmallerdimension.Atalaterstage,thismakesassemblydifficult.有一個模具注注塑工序，注注塑壓力超過過8000皮茲（1000帕斯卡）導致致尺寸偏差，，在后面階段段，裝配變的的很困難Aprocesscontrolonthecause(injectionpressure)mightbeasensoronthehydrauliccircuit.對這個原因（（注塑壓力））的過程控制制可能是一個個壓感應器ProcessControlExample過程控制案例例Aprocesscontrolonthefailuremode(smallerdimension)mightbeaninspectiononthedimension.對這種失效模模式（尺寸偏偏差）的流程程控制可能是是對每個部件件的尺寸進行行檢查FMEAExample-Step4.7

FMEA例子-步驟4.74.7.Estimatethedetectionforeachprocesscontrol.對每個過程控控制，估計可可測性FMEAExample-Step4.7:AIAG*DetectionGuidelinesAIAG的可測性指南南Note:AIAGistheAutomotiveIndustryActionGroup,whichcurrentlycompilestheFMEAstandardsfortheNorthAmericanAutoIndustry.備注：AIAG是汽車工業(yè)行行動集團的縮縮寫，目前北北美汽車工業(yè)業(yè)FMEA標準編寫者FMEAExample-Step5

FMEA例子-步驟55.ComputetheRiskPriorityNumberforeachcauseoffailure.對每個失效原原因，計算風險優(yōu)先先指數(shù)FMEAKeyPointsAboutStep5步驟5FMEA的重點KeypointsaboutStep5:對每個失效原原因，計算風風險優(yōu)先指數(shù)數(shù)Anyfailuremodewithaseverityof9or10mustbeidentifiedashighpriorityregardlessoftheRPN.任何嚴重性為為9-10的失效模式必必須看成優(yōu)先先級高的風險險指數(shù)AddressingthehighestRPNsismoreimportantthansettinganactualtarget(allRPNs<150,forexample).處理最高風險險指數(shù)（RPN）比設定目標標（所有RPNs<150為例）更重要要DifferentteamswillobtaindifferentRPNs.不同小組會產產生不同RPNsUsethehighRPNstoidentifycriticalissues(failuremodes,causesoffailures,keyprocessinputs).把高RPNs作為關鍵問題題（失效模式式，原因模式式，關鍵過程程輸入）5.ComputetheRiskPriorityNumberforeachcauseoffailure.對每個失效原原因，計算風風險優(yōu)先指數(shù)數(shù)FMEAExample-Step6

FMEA例子-步驟66.Developrecommendedactionsforhighprioritycausesoffailureand/orfailuremodes,.對高優(yōu)先級失失效原因或者者失效模式建建議采取行動動FMEAKeyPointsaboutStep6步驟6FMEA的重點KeypointsaboutStep6:步驟6的重點Reducingtheoccurrenceisthemostcosteffectivewaytoreducerisk.降低發(fā)發(fā)生頻頻率是是最經經濟有有效的的方法法來降降低風風險Actionsrecommendedshouldbelowcostandeffective.所建議議的行行動應應該低低成本本而且且有效效Trytothinkoflowcostactionsthatwillreducetheoccurrence.嘗試考考慮低低成本本行動動來降降低發(fā)發(fā)生頻頻率Makeuseofideasofallteammembersforimprovement.利用全全體成成員的的智慧慧對過過程進進行改改善6.Developrecommendedactionsforhighprioritycausesoffailureand/orfailuremodes,.對高優(yōu)優(yōu)先級級失效效原因因或者者失效效模式式，建建議采采取行行動MoreAboutFMEA-Step6步驟66.Assignresponsibilityandcompletiondeadlineforeachrecommendedaction,.對每個個建議議的行行動，，指定定責任任人和和完成成日期期FMEA-Step7FMEA-步驟77.Implementtheactionandverifyitseffectforeachrecommendedaction.對每個個建議議的行行動，，完成成并記記錄結結果FMEAKeyPointsAboutStep7步驟7FMEA的重點點KeypointsaboutStep7:步驟7的重點點Wasitimplemented?YesorNo.落實了了嗎？？是或或不是是Howeffectivewasit?Getdata.有效性性如何何？取取得數(shù)數(shù)據(jù)7.Implementtheactionandverifyitseffectforeachrecommendedaction.對每個個建議議的行行動，，完成成并記記錄結結果FMEAExample-Step8FMEA例子-步驟88.Re-assesstheseverity,occurrenceanddetectionrankingsandrecalculatetheRPNforeachimplementedaction對每項項完成成的行行動，，重新新估計計嚴重重性、、發(fā)生生頻率率和可可測性性并重重新計計算RPN。FMEAKeyPointsAboutStep8步驟8FMEA的重點點KeypointsaboutStep8:步驟8的重點點NeverrecalculateanRPNwithoutimplementinganimprovement!Guessingisnotallowed!在改進進行動動沒有有完成成前，，永遠遠不要重算算RPN，猜測測都不不允許許！Usually,itisdifficulttoreducetheseverityofafailuremode.However,sometimesafailuremodecanbeeliminated.通常，，很難難降低低失效效模式式的嚴嚴重性性，不過，，有時時能消消除失失效模模式。。ThemosteffectiveRPNreductionisreducingthelikelihoodofoccurrence.最有有效效降降低低RPN的方方法法是是減減低低可可能能的的發(fā)生生頻頻率率TheleasteffectiveRPNreductionisincreasinginspection(reducingthedetectionranking).Although,Poka-Yokecanreducethedetectionrankingandreducecost!RPN最沒沒效效的的降降低低方方法法是是增增加加檢檢查查（（降降低低探探測測性性等等級級）），，雖雖然然如如此此，，POKA-YOKE防錯錯方方法法能能降降低低探探測測等等級級并并降降低低成成本本8.Re-assesstheseve